Shows like CSI create the perception that crime scenes contain plenty of physical evidence and that technology can provide conclusive results. The reality is altogether different.

In a run-of-the-mill methamphetamine case tried in Oregon in October 2007, defense attorneys argued there was insufficient evidence because the prosecution didn't test a crack pipe for DNA. The prosecutor, Clatsop County, Ore., District Attorney Joshua Marquis, ultimately convinced jurors that DNA evidence wasn't necessary to prove beyond a reasonable doubt. But the fact that the defense played the forensic evidence card at all is a sign of the times.

It's become common for jurors to request forensic evidence in cases that were once thought routine. Defense attorneys also are challenging the prosecution if forensic evidence is absent, even in cases where it's not applicable.

The trend is a product of what jurors see on TV. Legal professionals call it the CSI Effect, and debate rages over its impact on the criminal justice system. The theory is that a proliferation of crime-scene television series, such as CBS stalwart CSI plants unrealistic expectations in the minds of jurors about how evidence is collected and processed.

If jurors believe what they see on TV, they might expect real-life investigators to collect and process evidence during the span of a TV commercial break: DNA test results in 15 minutes, fingerprints matched to a shady perpetrator, a mold of a knife wound poured with caulk.

Case Closed. Sort of.CSI and similar shows create the false perception that there's always plenty of physical evidence at a crime scene, and that technology exists to infallibly provide conclusive results on that evidence. The reality is altogether different. Crime scenes are messy, and most crime labs resemble high-school science labs, sometimes staffed with forensic technicians who possess high-school educations.

Most people in the criminal justice field agree that television crime shows affect real-life cases, but opinions differ on whether the impact is good or bad. The consensus is that jurors' heightened technological expectations prompt more evidence to be sent to labs for testing, which can unnecessarily slow the pace of trials and increase the cost of criminal investigations. On the other hand, the popularity of high-tech crime programs on TV has spurred nationwide interest in forensics, which could eventually cause life to imitate television.

Unreal ExpectationsCSI is one of the highest-rated TV shows, right up there with Dancing With the Stars and Desperate Housewives. Viewers are fascinated by beautiful-but-brainy, do-it-all cops who carry guns, question suspects, work with the district attorney, and use a battery of fancy tests that exclude the innocent and prove the guilt of the defendant.

To those who actually prosecute and defend criminal cases for a living, the image bears little resemblance to reality.

"I call them investigators in miniskirts," said Marquis, who is also a National District Attorneys Association vice president. "I mean, the formula is pretty clear. You always have an older male and a female lead who are kind of hot, and then a younger male and female who are very hot. It's done for dramatic license, and of course, they have CSI people doing arrests and investigations, which they never do [in real life]."

Real analysts do their work in the lab - they don't venture onto a crime scene, said Dan Krane, CEO and DNA specialist at Forensic Bioinformatics in Fairborn, Ohio.

"Going to a crime scene, collecting evidence and then performing tests upon it -and then coming to court and testifying about it - that's just not done by one person," he said. "It's a real production-line sort of approach."

And although at least some of the technology on TV is authentic, it's often portrayed as more agile and foolproof than it really is.

Marquis pointed to a CSI episode featuring a

gas chromatograph, which is a real instrument, but it was shown in an unlikely location: an investigator's van. "They cost about $60,000 to $80,000, and nobody in their right mind would ever mount one in a car. Because the first time you go over a pothole, you'd have to recalibrate the entire machine," he said, "but it is a real machine, and it's used for detecting drugs."

In the scene, an investigator tests for the presence of a drug by swabbing a sink at the crime scene with a probe, which looks like an elongated Q-tip. The probe turns bright blue, suggesting a positive test. "It's television, so it always has to be a glowing blue," Marquis said. "It's really a black sludge."

The material on the probe is then examined by the gas chromatograph, which produces a results chart within seconds. "It is, in fact, what would be generated in about two and a half weeks when you send it in for analysis," Marquis said. "So in that case, they weren't making stuff up; there are really gas chromatographs. But the process was so easy and so fast that I think it creates false expectations."

Shades of GrayReal-life crime lab equipment is big, bulky and not photogenic, according to Krane. "The equipment you see in CSI tends to be handheld and you get to focus more on the actor than the equipment." And unlike television gadgetry, the results produced by real tools often are ambiguous.

"In CSI, they have these sorts of magic lights they can shine on crime scenes that illustrate to them where the best evidence samples are," Krane said. "Black light really does help illuminate things you wouldn't see otherwise, but everything is simpler, easier and less complicated [on TV] - relative to what it is in the real world."

In real-life investigations, 50 percent to 75 percent of forensic evidence samples taken from crime scenes are difficult to interpret, according to Krane, due to degradation, contamination and small sample sizes. That leaves far more room for subjective analysis.

"The reality is," Marquis said, "that real crime is very messy, and in real life, it isn't as crisp as it is on TV. It raises unrealistic expectations about technology that really does exist and in a perfect world we would be able to do it."

Does It Matter?What's the practical impact of the CSI Effect? Legal practitioners disagree.

Defense attorney and DNA expert Robert Blasier downplays the danger. "I think the CSI Effect is grossly overrated," said Blasier, who worked for the defense on both the Phil Spector and O.J. Simpson trials. "Both sides in a case usually talk about the fact that it's not anywhere near close to real life. You always bring it up.

"I just don't think the jurors really confuse television with reality," he continued. "If there's a particular forensic test and you think a jury might have some unreal expectations, I always will bring it up in cross examination: 'You understand that this is not television and you can't get a DNA result over a 30-second commercial. It just doesn't work that way, and the DNA technology is still relatively primitive.'"

Barry Fisher, crime lab director of the Los Angeles County Sheriff's Department, called the CSI Effect "media spin," but he admitted it can alter cases. "One of the things that might happen is we're asked to do more tests than we might be asked to do otherwise," he said. "One of the things district attorneys often argue is, we have to do these tests in anticipation of them being raised [as questions] by the defense."

Marquis said he put crime technicians on the witness stand for

four hours in one case to discuss the tests that weren't done and why they weren't necessary. "Basically I did it because, if we didn't, the implication would be that we were hiding something or failed to do something."

And although DNA can be incredibly helpful in the right situation, it's not a magic bullet in every crime, he added. "DNA helps in a lot of cases, but there are a lot of cases in which it doesn't do you any good at all, like a consent rape case."

Useful or not, today's juries simply demand more forensic evidence, according to Susan Riseling, chief of police for the University of Wisconsin-Madison. And those extra tests increase costs and slow the pace of criminal cases.

"CSI has led to a test-everything mindset. When there is a lot of blood and you take, say, 35 samples at a scene, you test 12 and want to stop there, but the defense then wants to argue that the lab didn't test all 35," she said. "Blood spatters the same way; splatter patterns can have lots of samples, and labs test a percentage of them. These take time and money, and cases pile up."

Riseling calls DNA the new fingerprint. "When fingerprints first came into being forensically, juries wanted to see the fingerprint evidence," she said. "When there were no fingerprints, people doubted the person was really there."

Such a scenario may have played out in the 2005 Robert Blake murder case. A Los Angeles jury acquitted the actor because of a lack of forensic evidence tying him to the murder of his wife. That verdict prompted Los Angeles District Attorney Steve Cooley to label the jury "incredibly stupid."

Life Imitates ArtAnother potential impact of the CSI Effect is greater public attention on - and more appreciation for - forensics facilities.

For instance, the CSI shows may have helped Los Angeles County get a new $102 million forensics center that was needed for years and finally opened in September 2007. The popularity of the shows and the subsequent interest in forensic science, helped focus attention on the need for a better facility as elected officials decided how to spend tax dollars.

"[These TV shows are] really helpful because they keep the issue in front of the public eye," Fisher said, adding that the county's old facility was so cramped "you had to go into the hallway to change your mind."

"Today, the only familiarity the average person has with a forensics lab is it's this wonderful pristine, sciencelike environment," said Kimberlianne Podlas, an attorney and assistant professor of media law and ethics at the University of North Carolina at Greensboro. The reality is, crime labs are cramped.

But Podlas, who has researched the CSI Effect, said there's nothing new about the public having high and maybe unreasonable expectations for crime-solving technology. "I kind of think there's always a tech effect going on, no matter the decade," she said.

With the justice system's acknowledgment in recent years that eyewitness testimony is often incorrect, the desire for more evidence isn't harmful to the system, according to Podlas. "I don't think it's a bad thing to have jurors out there who wonder, 'Well yeah, I am used to seeing people bring fingerprint evidence. You've got that little old lady who wears glasses the size of four plate glass windows saying this is the guy who stole the jewelry out of the case; I'm not sure I believe her identification."'

Foretelling the Future?Perhaps the biggest impact of the CSI Effect has been to spur

interest in forensics among young people. Science and forensics programs are proliferating at colleges and universities around the country.

"When I go out and do career days and talk to high-school and college students, people are really interested in becoming forensic scientists now," Marquis said. "Although, I don't think they realize how much work it is."

That could mean an influx of good people to the field - a factor that's more important than slick new equipment, Fisher said.

"The most important thing in crime labs today is the quality of the staff," he said. "Most of the things we do are labor intensive. It's not so much the equipment that solves the crime; it's the quality of the people who are using the equipment, and their ability to recognize things they're looking at and figure out how it's related to a particular case. That's oftentimes the key between a successful investigation and one that's not."

Krane agreed, saying the popularity of fictional crime shows could boost the quality of both real-life analysts and the technology they use.

"It's conceivable that in another 10 or 15 years, there may even be handheld things you could use at a crime scene as opposed to the refrigerator-sized things that are the workhorses right now. Analysts down the road will be better, smarter, faster - and maybe even better looking."